documentation: poky-ref-manual - updated the STAMP glossary description.

(From yocto-docs rev: 63720ee98bc9dd4eaa574784e7aa1ccd20822e80)

Signed-off-by: Scott Rifenbark <scott.m.rifenbark@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

documentation/poky-ref-manual/ref-variables.xml

@@ -2320,9 +2320,12 @@ recipes-graphics/xorg-font/font-alias_1.0.3.bb:PR = "${INC_PR}.3"
         <glossentry id='var-STAMP'><glossterm>STAMP</glossterm>
             <glossdef>
                 <para>
-                    Specifies the main part of the pathname and filename for stamp
-                    files for a particular recipe.
-                    <filename>STAMP</filename> is more than just the directory.
+                    Specifies the base path used to create recipe stamp files.
+                    The path to an actual stamp file is constructed by evaluating this
+                    string and then appending additional information. 
+                    Currently, the default assignment for <filename>STAMP</filename>
+                    as set in the <filename>meta/conf/bitbake.conf</filename> file
+                    is:
                     <literallayout class='monospaced'>
      STAMP = "${TMPDIR}/stamps/${MULTIMACH_TARGET_SYS}/${PN}-${EXTENDPE}${PV}-${PR}"
                     </literallayout>